Aleochara bipustulata (Linnaeus, 1760)

This species is widespread throughout Europe from the northern Mediterranean borders north to the UK and the far north of Fennoscandia, it is known to be generally common from lowlands to the upper tree line in mountain regions but many older records need to be confirmed as European workers did not recognize the distinction between the present species and the closely similar A. verna Say, 1836 until this was explained by Lohse (1986), similarly the wider Palaearctic distribution remains unclear but it is known to be widespread and to extend into Northern India. The species has long been known from North America as populations were imported during the 20th century for the biological control of various crop pests, most notably the cabbage root fly (Delia radicum L.), but recent work has shown that these belong to two similar species, A. verna and A. bilineata Gyllenhal, 1810, and it is now doubtful whether the present species has ever been present. In the UK it is generally common throughout England and Wales, though less so in the West Country, and sporadic and generally rare further north to the Scottish Highlands and in Northern Ireland. Adults are present year-round; they are active over a long season from early spring with most records between June and August. They occur in most not too wet habitats and are associated with all kinds of decaying organic matter; most frequently among sheep, horse and cattle dung and commonly in compost and among carrion and decaying vegetation but they may be found in a wide range of situations such as decaying fungi, bird nests and canine droppings. Adults feeding habits are poorly understood, they were said to predate diptera eggs but this is yet to be investigated and under laboratory conditions they have been observed consuming their own eggs and predating early instar diptera larvae. Larvae are known to parasitize a range of diptera pupae, entering as first instars and developing and pupating within, the entire life-cycle takes about one month and in northern Europe there are three generation each year. Adults may be sampled from dung or by sieving organic material, they fly over dung pasture in warm weather and can be attracted by disturbing crusted dung pats, through the winter they are often present in flood refuse and tussock samples and they sometimes occur among extraction samples of decaying vegetation.